Chemical agent resistant coating compositions

ABSTRACT

A chemical agent resistant coating composition can include a fluoropolymer, a flatting agent, and a hydrophobic additive. When the composition is applied to a substrate and cured as a coating, the coating has an 85° gloss of less than 3.5, a water contact angle of greater than 80°, and desorbs a maximum of 180 micrograms of bis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolyl methylphosphonofluoridate, according to testing under MIL-PRF-32348. A method of preparing chemical agent resistant coating compositions and substrates at least partially coated with the chemical agent resistant coating compositions are also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/948,140, filed Mar. 5, 2014, the entire contents of which is herebyincorporated by reference.

NOTICE OF GOVERNMENT SUPPORT

This invention was made with Government support under Contract No.W912HQ-13-C-0007 awarded by the Strategic Environmental Research andDevelopment Program.

FIELD OF THE INVENTION

The present invention relates to chemical agent resistant coatingcompositions, methods of making such coating compositions, andsubstrates at least partially coated with a chemical agent resistantcoating composition.

BACKGROUND OF THE INVENTION

Chemical agent resistant coatings (also referred to as “CARC”) arecommonly applied to military equipment, vehicles, and aircrafts that canbe exposed to chemical and biological agents. Chemical agent resistantcoatings resist biological and chemical agents. After being exposed tobiological and chemical agents, biological and chemical agents may thenbe washed from the surface of the coatings during a decontaminationprocess. As such, chemical agent resistant coatings are also designed toresist decontamination wash solutions. In addition, certain militaryspecifications require that these coatings have an extremely low glossto minimize visual detection due to glare or reflection from lightsources.

While chemical agent resistant coatings have been developed over theyears, the types of chemical agent resistant coatings currentlyavailable are limited. It is, therefore, desirable to provide newchemical agent resistant coatings.

SUMMARY OF THE INVENTION

The present invention is directed to a chemical agent resistant coatingcomposition comprising: a fluoropolymer; a flatting agent that comprisesat least 10 weight % of the composition based on the total solid weightof the coating composition; and a hydrophobic additive that includes awax. When the composition is applied to a substrate and cured as acoating, the coating has an 85° gloss of less than 3.5, a water contactangle of greater than 80°, and desorbs a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate according to testing under MIL-PRF-32348(November 2010).

The present invention is also directed to a method of preparing achemical agent resistant coating composition. The method comprisesmixing a fluoropolymer, a flatting agent such that the flatting agentcomprises at least 10 weight % of the composition based on the totalsolid weight of the coating composition, and a hydrophobic additive thatincludes a wax so that when the coating composition is applied to asubstrate and cured as a coating, the coating has an 85° gloss of lessthan 3.5, a water contact angle of greater than 800, and desorbs amaximum of 180 micrograms of bis(2-chloroethyl) sulfide and a maximum of40 micrograms of O-pinacolyl methylphosphonofluoridate according totesting under MIL-PRF-32348 (November 2010).

A substrate at least partially coated with the chemical agent resistantcoating compositions is also described herein.

DESCRIPTION OF THE INVENTION

For purposes of the following detailed description, it is to beunderstood that the invention may assume various alternative variationsand step sequences, except where expressly specified to the contrary.Moreover, other than in any operating examples, or where otherwiseindicated, all numbers expressing, for example, quantities ofingredients used in the specification and claims are to be understood asbeing modified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard variation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

In this application, the use of the singular includes the plural andplural encompasses singular, unless specifically stated otherwise. Inaddition, in this application, the use of “or” means “and/or” unlessspecifically stated otherwise, even though “and/or” may be explicitlyused in certain instances. Further, in this application, the use of “a”or “an” means “at least one” unless specifically stated otherwise. Forexample, “a” fluoropolymer, “a” flatting agent, “a” hydrophobicadditive, “an” acrylic resin, and the like refer to one or more of anyof these items.

As indicated, the present invention is directed to a chemical agentresistant coating composition that can include a fluoropolymer, aflatting agent, and a hydrophobic additive. As used herein, a “chemicalagent resistant coating composition” refers to a coating compositionthat when deposited onto a substrate and cured as a coating, resistsbiological and chemical agents. For example, chemical agent resistantcoatings deposited from the compositions described herein resistbis(2-chloroethyl) sulfide (also known as Mustard Gas or HD) andO-pinacolyl methylphosphonofluoridate (also referred to as Soman or GD).Chemical agent resistant coatings deposited from the compositionsdescribed herein can also resist other chemical and biological agentsknown in the art.

As previously noted, the chemical agent resistant coating compositionscan include a fluoropolymer. As used herein, a “polymer” refers tooligomers and both homopolymers and copolymers. The term “resin” is usedinterchangeably with “polymer”. Further, the term “fluoropolymer” refersto polymers and copolymers (including polymers having two or moredifferent monomers, including for example terpolymers) having a fluorineatom.

Non-limiting examples of fluoropolymers that can be used to form thechemical agent resistant coating compositions of the present inventioninclude polyvinylidene fluoride (PVDF), polyhexafluoropropylene (PHFP),polytetrafluoroethylene (PTFE), polyperfluoromethylvinylether (PMVE),and combinations thereof, as well as copolymers and terpolymers thereof.For example, the fluoropolymer can be a chlorotrifluoroethylenecopolymer, such as the chlorotrifluoroethylene copolymer commerciallyavailable from Asahi Glass Co. under the trade name LUMIFLON®.

The fluoropolymers used with the coating compositions of the presentinvention can be in solid or liquid form. For instance, thefluoropolymer can be a solid polyvinylidene fluoride (PVDF), such as thesolid polyvinylidene fluoride (PVDF) commercially available from Arkemaunder the trade name KYNAR®. Alternatively, the fluoropolymer can be aliquid form of polyvinylidene fluoride (PVDF).

The fluoropolymer can comprise at least 5 weight %, at least 8 weight %,at least 10 weight %, at least 20 weight %, at least 30 weight %, or atleast 40 weight %, based on the total solids weight of the coatingcomposition. The fluoropolymer can comprise at most 70 weight %, at most60 weight %, or at most 50 weight %, based on the total solids weight ofthe composition. The fluoropolymer can also comprise a range such asfrom 5 to 70 weight %, from 8 to 60 weight %, or from 10 to 50 weight %,based on the total solids weight of the composition.

As indicated above, the chemical agent resistant coating compositionscan also include a flatting agent. As used herein, the term “flattingagent” refers to a material added to a coating composition to reduce thegloss of a coating formed from the composition. The term “flattingagent” is interchangeable with the term “matting agent”.

Non-limiting examples of suitable flatting agents that can be used withthe coating compositions described herein include metal hydroxides,ground fiberglass, metal oxides, silicas, hyperbranched (meth)acrylicpolymers, polyurea particles, polyolefin particles, and mixturesthereof. The flatting agents used with the coating compositionsdescribed herein can also have a melting point of greater than 190° C.,or greater than 200° C., or greater than 210° C., or greater than 220°C.

When silica is used as a flatting agent with the coating composition, itcan be used in various forms including, but not limited to, amorphous,aerogel, diatomaceous, hydrogel, fumed, and combinations thereof.

As used herein, the term “hyperbranched (meth)acrylic polymer” refers toa polymer having a main polymer chain and at least two branching pointsalong the main polymer chain. The hyperbranched (meth)acrylic polymersof the present invention can exhibit an alpha parameter derived from theMark-Houwink equation of 0.2 to 0.7, or an alpha parameter derived fromthe Mark-Houwink equation of 0.3 to 0.6. The Mark-Houwink relationshipbetween molar mass (M) and intrinsic viscosity (η) ([η.]=K.Mα providesinformation about the structure of the polymer. The alpha parameterindicates the degree of branching and can be determined by multidetection size-exclusion chromatography as described by Paillet et al,Journal of Polymer Science Part A: Polymer Chemistry, 2012, 50,2967-2979, which is incorporated by reference herein. Further, the term(meth)acrylic refers to acrylic and methacrylic, as well as theiresters.

The hyperbranched (meth)acrylic polymers can be hydroxyl or carboxylgroup functional. Non-limiting examples of hyperbranched (meth)acrylicpolymers and methods of preparing them are described in United StatesPatent Application Publication No. 2014/0275362 at paragraphs [0016] to[0029], which are incorporated by reference herein.

The hyperbranched (meth)acrylic polymer can have a weight averagemolecular weight of greater than 3,000 g/mol, or greater than 10,000g/mol, or greater than 100,000 g/mol, or at least 200,000 g/mol, asdetermined by standard gel permeation chromatography.

As noted, the flatting agent can include ground fiberglass. As usedherein, “ground fiberglass” refers to continuous strands of glass fibersthat have been extruded into fine filaments and ground to a desiredsize. The ground fiberglass can have an average size dimension of 30 to70 microns, or 35 to 60 microns, or 35 to 55 microns, or 40 to 50microns. The ground fiberglass can also have an average size dimensionthat allows the fiberglass to be passed through a 250 to 375 meshfilter, or a 275 to 350 mesh filter, or a 300 to 350 mesh filter, or a325 mesh filter. As used herein, “average size dimension” refers to thesize of 50 weight percent or more of the ground fiberglass in a sample.

Non-limiting examples of metal hydroxides that can be used as a flattingagent include aluminum hydroxide, titanium hydroxide, cobalt hydroxide,iron hydroxide, chrome hydroxide, tin hydroxide, antimony hydroxide,manganese hydroxide, and combinations thereof. Non-limiting examples ofmetal oxides that can be used as a flatting agent include aluminumoxide, titanium oxide, cobalt oxide, iron oxide, chrome oxide, tinoxide, antimony oxide, manganese oxide, and combinations thereof. Themetal oxide can form crystal structures including, but not limited to,rutile, hematite, spinel, and combinations thereof.

Non-limiting examples of polyurea particles that can be used includethose commercially available from Albemarle Corp. under the trade namePERGOPAK® such as PERGOPAK® M3, M4, M5, and M6. Other non-limitingexamples include those commercially available from Deuteron GmbH underthe trade name Deuteron® MK and MK-FF.

Non-limiting examples of polyolefin particles that can be used as aflatting agent include polyethylene particles, polypropylene particles,and combinations thereof. Such particles can also be used as adispersion.

The flatting agent can comprise at least 10 weight %, at least 15 weight° %, at least 20 weight %, at least 30 weight %, or at least 40 weight %based on the total solid weight of the composition. The flatting agentcan also comprise at most 80 weight %, at most 70 weight %, at most 60weight %, or at most 50 weight %, based on the total solid weight of thecomposition. The flatting can also comprise a range such as from 10 to80 weight %, from 20 to 70 weight %, from 20 to 50 weight %, from 30 to40 weight %, or from 35 to 70 weight %, based on the total solid weightof the composition.

The flatting agents described herein can be added to help reduce thegloss of a coating. For example, the flatting agent can be added to helpobtain a chemical agent resistant coating having an 85° gloss of lessthan 3.5, less than 2.5, less than 2, less than 1.5, less than 1, orless than 0.5. The flatting agent can also help obtain a chemical agentresistant coating having a 60° gloss of less than 3.5, less than 2.5,less than 2, less than 1.6, less than 1.5, less than 1, or less than0.5. The 60° and 85° gloss measurements are determined with aStatistical Novo-Gloss 200 gloss meter.

The coating compositions of the present invention can also include ahydrophobic additive. As used herein, the term “hydrophobic additive”refers to a material that can increase the water repellency of acoating. The hydrophobic additive used with the coating compositions ofthe present invention are compatible with the fluoropolymer, flattingagent, and other components described herein. The hydrophobic additivecan have a melting point of less than 130° C., or less than 120° C., orless than 110° C., or less than 100° C. Suitable hydrophobic additivesthat can be used with the coating compositions of the present inventioninclude, but are not limited to, waxes, such as fluorinated waxes forexample. Non-limiting examples of suitable waxes that can be usedinclude polytetrafluoroethylene wax, polytetrafluoroethylene-modifiedpolyethylene wax, polytetrafluoroethylene-modified polypropylene wax,carnauba wax, silicone wax, polyethylene wax, polypropylene wax,paraffinic wax, and mixtures thereof.

The hydrophobic additive can comprise at least 0.01 weight %, at least0.05 weight %, at least 0.1 weight %, at least 0.5 weight %, at least 1weight %, at least 2 weight %, at least 3 weight %, or at least 5 weight%, based on the total solid weight of the composition. The hydrophobicadditive can comprise at most 20 weight %, at most 15 weight %, or atmost 10 weight %, based on the total solid weight of the composition.The hydrophobic additive can also comprise a range such as from 0.01 to20 weight %, from 0.1 to 15 weight %, from 0.5 to 15 weight %, from 1 to10 weight %, or from 3 to 10 weight %, based on the total solid weightof the composition.

The chemical agent resistant coating compositions can comprise ahydrophobic additive, fluoropolymer, and flatting agent such that, whenapplied to a substrate as a coating, the coating has a water contactangle of greater than 80°, or greater than 90°, or greater than 100°, orgreater than 110°. The water contact angles may be measured with theKruss DSA 100. Methylene iodide and water may be used to determinesurface energy of panels. Typically, five drops of each liquid are usedwith the contact angles measured four seconds after deposition. Dropvolume of 2.0 μl for each liquid is used. Contact angles are analyzedusing the Owens-Wendt-Rabel and Kaelble method to calculate surfaceenergy. Temperature and humidity at the time of testing may be 73° F.and 49% RH.

In addition to extremely low gloss and high water contact angles,coatings deposited from the coating compositions comprising ahydrophobic additive, fluoropolymer, and flatting agent exhibit superiordurability and chemical resistance. For example, the chemical agentresistant coatings resist bis(2-chloroethyl) sulfide and O-pinacolylmethylphosphonofluoridate such that after exposure to these chemicalagents, the coatings desorb a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate, according to testing under United Statesmilitary specification MIL-PRF-32348 (November 2010), which isincorporated by reference herein in its entirety. Bis(2-chloroethyl)sulfide is commonly referred to as Mustard Gas or HD, and O-pinacolylmethylphosphonofluoridate is commonly referred to as Soman or GD. Thecoatings can also desorb a maximum of 80 micrograms, a maximum of 70micrograms, a maximum of 60 micrograms, a maximum of 50 micrograms, amaximum of 40 micrograms, a maximum of 30 micrograms, or a maximum of 20micrograms of bis(2-chloroethyl) sulfide. In addition, the coatings candesorb a maximum of 35 micrograms, a maximum of 30 micrograms, a maximumof 25 micrograms, or a maximum of 20 micrograms of O-pinacolylmethylphosphonofluoridate. The coatings deposited from the coatingcompositions described herein can resist various other chemical andbiological agents known in the art.

As further required by MIL-PRF-32348 (November 2010), the chemical agentresistant coatings are resistant to decontamination solutions. Forexample, the chemical agent resistant coatings were found to beresistant to super tropical bleach, a chlorinated lime, as tested inaccordance with MIL-PRF-32348 (November 2010).

Further, the chemical agent resistant coating compositions can alsoinclude a dispersible resin. The resin can be water or solventdispersible. For example, the resin can be a water dispersible acrylicresin having acid functionality. The term “water dispersible” means thatthe resin is a polymer or oligomer that is solubilized, partiallysolubilized, and/or dispersed in some quantity of a water solution withor without additional water soluble solvents. The solution, which can beused with the compositions described herein, can be at least 50% water,at least 60% water, at least 70% water, at least 80% water, at least 90%water, or 100% water, based on the total weight of the solution. Thesolution can also be less than 50% cosolvent, at most 40% cosolvent, atmost 30% cosolvent, at most 20% cosolvent, or at most 10% cosolvent,based on the total weight of the solution. Suitable cosolvents include,for example, aliphatic hydrocarbons, aromatic hydrocarbons, ketones,esters, glycols, ethers, ether esters, glycol ethers, glycol etheresters, alcohols, ether alcohols, phthalate plasticizers, N-methylpyrrolidone, and combinations thereof. Phthalate plasticizers includephthalates esters such as diethylhexyl phthalate, diisononyl phthalate,diisodecyl phthalate, dioctyl phthalate, and butyl benzyl phthalate.

The dispersible resin can also be solvent dispersible, such as a solventdispersible acrylic resin having acid functionality. A “solventdispersible” resin is a polymer or oligomer that is solubilized,partially solubilized, and/or dispersed in a solvent solution where themajority of the solution is a solvent other than water. Suitablesolvents that make up the majority of such a solution, which can be usedwith the compositions described herein, include, but are not limited to,any of the cosolvents previously described. For example, the solventsolution can comprise at least 50% cosolvent, at least 60% cosolvent, atleast 70% cosolvent, at least 80% cosolvent, at least 90% cosolvent, or100% cosolvent, based on the total weight of the solution. Such solventsolutions can also include less than 50% water, at most 40% water, atmost 30% water, at most 20% water, or at most 10% water, based on thetotal weight of the solution.

The dispersible resin can comprise at least 50 weight % methyl(meth)acrylate, at least 60 weight % methyl (meth)acrylate, or at least70 weight % methyl (meth)acrylate, based on the total weight of theresin, as determined by standard gel permeation chromatography.

The dispersible resin can also have an acid value of at least 10 mgKOH/g, at least 20 mg KOH/g, or at least 30 mg KOH/g. The dispersibleresin can have an acid value of at most 100 mg KOH/g, at most 90 mgKOH/g, at most 80 mg KOH/g, or at most 60 mg KOH/g. The dispersibleresin can also have an acid value range such as from 10 to 100 mg KOH/g,from 5 to 60 mg KOH/g, or from 20 to 40 mg KOH/g.

Further, the dispersible resin can have a glass transition temperatureof greater than 40° C., or greater than 50° C., or greater than 60° C.,or greater than 70° C. The glass transition temperature (Tg) isdetermined by differential scanning calorimetry.

The dispersible resin can comprise at least 1 weight %, at least 2weight %, or at least 5 weight % of the coating composition, based onthe total solid weight of the composition. The dispersible resin cancomprise at most 20 weight %, at most 15 weight %, at most 10 weight %,or at most 7 weight % of the coating composition, based on the totalsolid weight of the composition. The dispersible resin can also comprisea range such as from 1 to 20 weight %, from 2 to 15 weight %, or from 2to 7 weight % of the coating composition, based on the total solidweight of the coating composition.

A crosslinker can also be used with the chemical agent resistant coatingcompositions. As used herein, a “crosslinker” refers to a moleculecomprising two or more functional groups that are reactive with otherfunctional groups and which is capable of linking two or more monomersor polymer molecules through chemical bonds. The crosslinker can be insolid or liquid form. Non-limiting examples of suitable crosslinkersinclude hydroxyalkyl amides, glycidyl functional acrylics,triglycidylisocyanurate, carbodiimides, such as those commerciallyavailable from Dow as UCARLINK, melamines, such as those available fromCytec as CYMEL®, and blocked isocyanates, such as those available fromBayer as CRELAN®.

Alternatively, the chemical agent resistant coating compositions may besubstantially free, essentially free, or completely free of acrosslinker. The term “substantially free” as used in this context meansthe coating compositions contain less than 1000 parts per million (ppm),“essentially free” means less than 100 ppm, and “completely free” meansless than 20 parts per billion (ppb) of a crosslinker.

The coating compositions of the present invention can also include otheroptional materials well known in the art of formulating coatings. Forexample, the coating compositions of the present invention can alsoinclude a colorant. As used herein, “colorant” refers to any substancethat imparts color and/or other opacity and/or other visual effect tothe composition. The colorant can be added to the coating in anysuitable form, such as discrete particles, dispersions, solutions,and/or flakes. A single colorant or a mixture of two or more colorantscan be used in the coatings of the present invention.

Example colorants include pigments (organic or inorganic), dyes andtints, such as those used in the paint industry and/or listed in the DryColor Manufacturers Association (DCMA), as well as special effectcompositions. A colorant may include, for example, a finely dividedsolid powder that is insoluble, but wettable, under the conditions ofuse. A colorant can be organic or inorganic and can be agglomerated ornon-agglomerated. Colorants can be incorporated into the coatings by useof a grind vehicle, such as an acrylic grind vehicle, the use of whichwill be familiar to one skilled in the art.

Example pigments and/or pigment compositions include, but are notlimited to, carbazole dioxazine crude pigment, azo, monoazo, diazo,naphthol AS, salt type (flakes), benzimidazolone, isoindolinone,isoindoline and polycyclic phthalocyanine, quinacridone, perylene,perinone, diketopyrrolo pyrrole, thioindigo, anthraquinone, indanthrone,anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone, dioxazine,triarylcarbonium, quinophthalone pigments, diketo pyrrolo pyrrole red(“DPPBO red”), titanium dioxide, carbon black, and mixtures thereof. Theterms “pigment” and “colored filler” can be used interchangeably.

Example dyes include, but are not limited to, those that are solventand/or aqueous based such as phthalo green or blue, iron oxide, bismuthvanadate, anthraquinone, and peryleneand quinacridone.

Example tints include, but are not limited to, pigments dispersed inwater-based or water miscible carriers such as AQUA-CHEM 896commercially available from Degussa, Inc., CHARISMA COLORANTS andMAXITONER INDUSTRIAL COLORANTS commercially available from AccurateDispersions Division of Eastman Chemical, Inc.

The chemical agent resistant coating compositions can include pigmentparticles that can comprise at least 1 weight %, at least 3 weight %, orat least 5 weight % of the coating composition, based on total solidweight of the coating composition. The pigment particles can comprise atmost 70 weight %, at most 50 weight %, or at most 25 weight % of thecoating composition, based on total solid weight of the coatingcomposition. The pigment particles that can also comprise a range suchas from 1 to 70 weight %, from 3 to 50 weight %, or from 5 to 25 weight% of the coating composition, based on total solid weight of the coatingcomposition.

In addition, the coating compositions can also include additionalfilm-forming resins. For example, the coating compositions can alsoinclude certain amounts of polyurethanes, polyesters, polyamides,polyethers, polysiloxanes, epoxy resins, vinyl resins, copolymersthereof, and combinations thereof. As used herein, a “film-formingresin” refers to a resin that can form a self-supporting continuous filmon at least a horizontal surface of a substrate upon removal of anydiluents or carriers present in the composition or upon curing.

Alternatively, the coating compositions may be substantially free,essentially free, or completely free of additional film-forming filmssuch as those previously described. The term “substantially free” asused in this context means the coating compositions contain less than1000 parts per million (ppm), “essentially free” means less than 100ppm, and “completely free” means less than 20 parts per billion (ppb) ofadditional film-forming films, such as those previously described.

Other non-limiting examples of materials that can be used with thecoating compositions of the present invention include plasticizers,abrasion resistant particles, corrosion resistant particles, corrosioninhibiting additives, fillers including, but not limited to, micas,talc, clays, and inorganic minerals, anti-oxidants, hindered amine lightstabilizers, UV light absorbers and stabilizers, surfactants, flow andsurface control agents, thixotropic agents, reactive diluents,catalysts, reaction inhibitors, and other customary auxiliaries.

The present invention is also directed to a method of preparing chemicalagent resistant coating compositions. The method can comprise mixing thefluoropolymer, flatting agent, and hydrophobic additive such that whenthe coating composition is applied to a substrate and cured as acoating, the coating has a low gloss, high water contact angle, andexcellent chemical resistance. For instance, the fluoropolymer, flattingagent, and hydrophobic additive can be mixed together such that when thecoating composition is applied to a substrate and cured as a coating,the coating has an 85° gloss of less than 3.5, a water contact angle ofgreater than 80°, and desorbs a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate, according to testing under MIL-PRF-32348(November 2010). The method can also include mixing any of the othercomponents identified above including, but not limited to, a dispersibleacrylic resin, crosslinker, and/or colorant.

The method of preparing the chemical agent resistant coatingcompositions can include dispersing the mixture in water. Alternatively,the mixture can be dispersed in a solvent including, but not limited to,any of the solvents described above. The chemical agent resistantcoating composition can then be applied to a substrate as a liquid andcured to form a chemical agent resistant coating. “Curing” refers tobond formation resulting in the formation of a crosslinked coating. Itwill be appreciated that the cure parameters will vary depending on thefluoropolymer, flatting agent, hydrophobic additive, optionaldispersible resin, and other components, but such parameters can bereadily determined by one skilled in the art.

The chemical agent resistant coating composition can also be applied toa substrate as a powder rather than as a liquid. As such, the method canfurther include drying the mixture. The mixture can be dried accordingto any means known in the art. Suitable methods for drying are spraydrying, tray drying, freeze drying, fluid bed drying, single and doubledrum drying, flash drying, swirl drying, and numerous other evaporationtechniques. The dry mixture can also be ground to a desired particlesize. Grinding can be accomplished by any means known in the art, suchas through the use of an air classifying mill.

As indicated, the fluoropolymer can be used in solid or liquid form. Thesolid or liquid fluoropolymer can be dispersed in water or solvent withthe flatting agent, hydrophobic additive, and other components, andoptionally dried to form a powder using the techniques described above.

The chemical agent resistant coating compositions can be applied to awide range of substrates known in the coatings industry. For example,the chemical agent resistant coating compositions can be applied toautomotive substrates, industrial substrates, packaging substrates, woodflooring and furniture, apparel, electronics, including housings andcircuit boards, glass and transparencies, sports equipment, includinggolf balls, and the like. These substrates can be, for example, metallicor non-metallic. Metallic substrates include, but are not limited to,tin, steel (including electrogalvanized steel, cold rolled steel,hot-dipped galvanized steel, among others), aluminum, aluminum alloys,zinc-aluminum alloys, steel coated with a zinc-aluminum alloy, andaluminum plated steel. Non-metallic substrates include polymeric,plastic, polyester, polyolefin, polyamide, cellulosic, polystyrene,polyacrylic, poly(ethylene naphthalate), polypropylene, polyethylene,nylon, EVOH, polylactic acid, other “green” polymeric substrates,poly(ethyleneterephthalate) (PET), polycarbonate, polycarbonateacrylobutadiene styrene (PC/ABS), polyamide, wood, veneer, woodcomposite, particle board, medium density fiberboard, cement, stone,glass, paper, cardboard, textiles, leather both synthetic and natural,and the like.

The chemical agent resistant coating compositions of the presentinvention are particularly useful when applied to substrates used formilitary equipment, vehicles, and aircrafts. For example, the chemicalagent resistant coating compositions can be applied to pretreated coldrolled steel, galvanized steel, aluminum, or a combinations thereof thatare found on military equipment, vehicles, and aircrafts.

The coatings of the present invention can be applied by any meansstandard in the art, such as electrocoating, spraying, electrostaticspraying, dipping, rolling, brushing, and the like. The coatings of thepresent invention can be applied to a dry film thickness of at least 0.5mil, 1 mil, or 2 mils. The coatings of the present invention can beapplied to a dry film thickness of at most 5 mils, at most 4 mils, or atmost 3 mils. The coatings of the present invention can also be appliedat a dry film thickness range such as from 0.5 mil to 5 mils, such asfrom 1 mil to 4 mils, or from 2 mils to 3 mils.

The coating compositions of the present invention may also be used aloneor in combination with primers, basecoats, and/or topcoats. A “primercoating composition” refers to coating compositions from which anundercoating may be deposited onto a substrate in order to prepare thesurface for application of a protective or decorative coating system. Abasecoat refers to a coating composition from which a coating isdeposited onto a primer and/or directly onto a substrate optionallyincluding components (such as pigments) that impact the color and/orprovide other visual impact and which may be overcoated with aprotective and decorative coating system.

It will be appreciated from the following examples that the coatingcompositions described herein provide coatings having extremely lowgloss, high water contact angles, and superior chemical resistance,which meets the strict requirements to qualify the coatings as a CARC.The following examples are presented to demonstrate the generalprinciples of the invention. The invention should not be considered aslimited to the specific examples presented. All parts and percentages inthe examples are by weight unless otherwise indicated.

Example 1 Preparation of a Chemical Agent Resistant Coating Composition

A chemical agent resistant coating composition according to the presentinvention was prepared with the following ingredients shown in Table 1.

TABLE 1 Ingredients Weight (grams) LUMIFLON ® 710 LF ¹ 183.0 VESTAGON ®B 1400 ² 47.0 Tris(2,3-epoxypropyl)isocyanurate ³ 5.0 Benzoin ⁴ 1.5V-12600 Green ⁵ 17.15 G-8599 Green ⁶ 20.05 MAPICO ® Tan 20A ⁷ 6.21Carbazole Violet ⁸ 0.21 MODAFLOW ® ⁹ 2.5 IRGANOX ® 1076 ¹⁰ 1.1 DT 3329¹¹ 5.0 MARTINAL ® Aluminum Hydroxide ¹² 600.0 ¹ Chlorotrifluoroethylenecopolymer, commercially available from Asahi Glass. ² Polyisocyanateadduct having e-caprolactam blocked NCO-groups, commercially availablefrom Evonik Industries. ³ Trifunctional epoxy used as a crosslinkingagent. ⁴ 2-hydroxy-1,2-di(phenyl)ethanone used as an anti-gassingadditive. ⁵ Cobalt chromite based inorganic green color pigment,commercially available from Ferro Corporation. ⁶ Chromic oxide baseddark green pigment, commercially available from Elementis Chemical Corp.⁷ Dark tan magnesium ferrite pigment, commercially available fromRockwood Pigments. ⁸ Dioxazine blue tone pigment, commercially availablefrom Crenovo International Limited. ⁹ Flow modifier, commerciallyavailable from Cytec Industries. ¹⁰ Sterically hindered phenolicantioxidant, commercially available from Ciba Specialty Chemicals Corp.¹¹ Blend of wax and mercaptobenzothiazole, commercially available fromHuntsman Corp. ¹² Aluminum hydroxide, commercially available fromAlbemarle Corp.

The ingredients shown in Table 1 were mixed in a Henschel mixer. Themixed ingredients were then hot melt mixed on a 19MM Baker Perkinsextruder at rotational speeds of 350 rps. After melt mixing, the mixturewas allowed to cool. The resulting mixture was then ground on a Micronunit ACM 1 to a particle size of 30 microns.

Example 2 Preparation of a Chemical Agent Resistant Coating Composition

A chemical agent resistant coating composition according to the presentinvention was prepared with the following ingredients shown in Table 2.

TABLE 2 Ingredients Weight (grams) Acrylic Resin ¹³ 177.7 V-12600 Green⁵ 9.6 G-8599 Green ⁶ 14.3 MAPICO ® Tan 20A ⁷ 3.0 Carbazole Violet ⁸0.130 Pigment Black 7 ¹⁴ 0.024 MAPICO ® Black Iron Oxide ¹⁵ 0.22Portafill ® A40 ¹⁶ 132.0 Methyl Isobutyl Ketone 6.4 TINUVIN ® 144 ¹⁷ 1.0TINUVIN ® 900 ¹⁸ 0.55 LANCO ™ 1778 ¹⁹ 7.7 PRIMID ® XL552/deionized 11.0water mix (1:1 ratio) ²⁰ KYNAR@ 500 ²¹ 56.0 ¹³ Acrylic resin havinggreater than 50 weight % methyl (meth)acrylate based on the total weightof the acrylic resin, less than 12 weight % methacrylic acid based onthe total weight of the acrylic resin, and a glass transitiontemperature of about 94° C. ¹⁴ Carbon black pigment. ¹⁵ Iron oxide blackpigment, commercially available from Rockwood Pigments. ¹⁶ Mattingfiller produced from aluminum hydroxide, commercially available fromSibelco Specialty Mineral Europe. ¹⁷ Light stabilizer of the hinderedamine class, commercially available from Ciba Specialty Chemicals Corp.¹⁸ UV absorber of the hydroxyphenylbenzotriazole class, commerciallyavailable from Ciba Specialty Chemicals Corp. ¹⁹ MicronizedPTFE-modified polyethylene wax, commercially available from LubrizolAdvanced Materials Inc. ²⁰ Hydroxyalkylamide crosslinker, commerciallyavailable from EMS-GRILTECH, mixed with deionized water at a ratio of1:1. ²¹ Solid polyvinylidene fluoride, commercially available fromArkema.

The ingredients shown in Table 2 were weighed into a 1000 ml containerand mixed with a Cowles mixer for 20 to 40 minutes or until a particlesize of +6 was obtained, as measured on a Hegman's gauge. The mixturewas dried by conventional techniques known in the art. The resultingsheet was then ground on a Micron unit ACM 1 to a particle size of 30microns.

Example 3 Preparation of a Chemical Agent Resistant Coating Composition

A chemical agent resistant coating composition according to the presentinvention was prepared with the following ingredients shown in Table 3.

TABLE 3 Ingredients Weight (grams) Acrylic Resin ²² 177.7 V-12600 Green⁵ 9.6 G-8599 Green ⁶ 14.3 MAPICO ® Tan 20A ⁷ 3.0 Carbazole Violet ⁸0.130 Pigment Black 7 ¹⁴ 0.024 MAPICO ® Black Iron Oxide ¹⁵ 0.22 TEXO ®ground fiberglass ²³ 90 Methyl Isobutyl Ketone 6.4 TINUVIN ® 144 ¹⁷ 1.0TINUVIN ® 900 ¹⁸ 0.55 LANCO ™ 1778 ¹⁹ 7.7 PRIMID ® XL552/deionized 11.0water mix (1:1 ratio) ²⁰ KYNAR ® 500²¹ 56 ²² Acrylic resin havinggreater than 50 weight % methyl (meth)acrylate based on the total weightof the acrylic resin, less than 12 weight % methacrylic acid based onthe total weight of the acrylic resin, and a glass transitiontemperature of about 69° C. ²³ TEXO ® ground fiberglass is washed,ground and filtered through a 325 mesh filter - supplied by PPGIndustries.

The ingredients shown in Table 3 were weighed into a 1000 ml containerand mixed with a Cowles mixer for 20 to 40 minutes or until a particlesize of +6 was obtained, as measured on a Hegman's gauge. The mixturewas dried by conventional techniques known in the art. The resultingsheet was then ground on a Micron unit ACM 1 to a particle size of 30microns.

Example 4 Preparation and Evaluation of Chemical Agent ResistantCoatings

The chemical agent resistant coating compositions of Examples 1-3 wereeach sprayed onto a cold rolled steel metal panel as a powdercomposition with an electrostatic spray at 75 k. The coatingcompositions were sprayed at a thickness of 2 to 3 mils. Panels werethen baked for 15-25 minutes at a temperature of 425° F. The resultingcoatings were evaluated for various properties, the results of which areshown in Table 4.

TABLE 4 Performance/Physical EXAMPLE 1 EXAMPLE 2 Example 3 PropertiesTesting Results Testing Results Testing Results 60° Gloss ²⁴ 1 0.2 0.485° Gloss ²⁴ 1.4 0.3 0.5 MEK Double Rubs ²⁵ +100 +100 +100 Adhesion ²⁶5B 5B 5B Recoat ²⁷ Pass Pass Pass Ra Value ²⁸ 200 μinch 270 μinch 260μinch CARC HD <3 μg <13 μg 42 μg Desorption ²⁹ CARC GD <3 μg <13 μg 28μg Desorption ³⁰ Super Tropical Bleach Pass Pass Pass Resistance ³¹ 340QUV 1000 hrs ³² 100% gloss 100% gloss 100% gloss retention retentionretention WOM 1000 hrs ³³ 100% gloss 100% gloss 100% gloss retentionretention retention Water Contact 84° 110° 105° Angle ³⁴ ²⁴ 60° and 85°gloss was measured with a Statistical Novo-Gloss 20° gloss meter,available from Paul N. Gardner Company, Inc. ²⁵ MEK double rubs refersto the chemical resistance of the coatings to methyl ethyl ketone (MEK),evaluated in accordance with ASTM 04752-10(2015). ²⁶ Adhesion measuredin accordance with ASTM D3359-09e2. Adhesion is assessed on a scale of 0to 5. ²⁷ Recoating was performed and evaluated in accordance withMIL-PRF-32348 (November 2010), section 4.6.13, which requires that therecoating of a dried film produce no lifting, softening, or other filmirregularity. ²⁸ Ra value is the surface roughness of a coating, whichwas measured with a Surtronic 25 profilometer. ²⁹ CARC HD is the measureof the retention of bis(2-chloroethyl) sulfide in accordance withMIL-PRF-32348 (November 2010) section 3.6.10 and 4.6.19 type IIIcoatings. ³⁰ CARC GD is the measure of the retention of O-pinacolylmethylphosphonofluoridate in accordance with MIL-PRF-32348 (November2010) section 3.6.10 type III coatings. ³¹ Super tropical bleach is achlorinated lime and is used to test chemical resistance in accordanceMIL-PRF-32348 (November 2010), section 4.6.18. ³² Gloss retention testmethod according to ASTM D4214-07. ³³ Gloss retention test methodaccording to SAE J2025-1989. ³⁴ Water contact angles were measured withthe Kruss DSA 100. Methylene iodide and water were used to determinesurface energy of panels. Five drops of each liquid were used with thecontact angles measured four seconds after deposition. Drop volume of2.0 μl for each liquid was used. Contact angles were analyzed using theOwens-Wendt-Rabel and Kaelble method tocalculate surface energy.Temperature and humidity at the time of testing were 73° F. and 49% RH.

As shown in Table 4, coatings deposited from the chemical agentresistant coatings compositions of the present invention exhibitedextremely low gloss, high water contact angles, and superior chemicalresistance to both Mustard Gas and Soman, as well as to other chemicals,including those used as decontamination solutions. The coatingsdeposited from the coating compositions of Examples 1-3 also exhibitedexcellent weather resistance, adhesion to substrates, and smoothness.

The present invention also includes the following clauses.

Clause 1: A chemical agent resistant coating composition comprising: afluoropolymer, a flatting agent comprising at least 10 weight % of thecomposition based on the total solids weight of the coating composition,and a hydrophobic additive comprising a wax, wherein when thecomposition is applied to a substrate and cured as a coating, thecoating has an 850° gloss of less than 3.5, a water contact angle ofgreater than 80°, and desorbs a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate, according to testing under MIL-PRF-32348.

Clause 2: The coating composition of clause 1, wherein the coating has awater contact angle of greater than 1000.

Clause 3: The coating composition of any of clauses 1-2, wherein thecoating desorbs a maximum of 80 micrograms of bis(2-chloroethyl) sulfideand a maximum of 35 micrograms of O-pinacolyl methylphosphonofluoridate.

Clause 4: The coating composition of any of clauses 1-3, wherein thefluoropolymer comprises polyvinylidene fluoride, chlorotrifluoroethylenecopolymer, or a mixture thereof.

Clause 5: The coating composition of any of clauses 1-4, wherein theflatting agent comprises a metal hydroxide, metal oxide, silica, ahyperbranched (meth)acrylic polymer, a polyurea particle, a polyolefinparticle, ground fiberglass, or mixtures thereof.

Clause 6: The coating composition of clause 5, wherein the fiberglasscomprises an average size dimension of 30 to 70 microns.

Clause 7: The coating composition of clause 1, wherein the wax is afluorinated wax.

Clause 8: The coating composition of clause 1, wherein the wax comprisespolytetrafluoroethylene wax, polytetrafluoroethylene-modifiedpolyethylene wax, polytetrafluoroethylene-modified polypropylene wax,polyethylene wax, polypropylene wax, paraffinic wax, carnauba wax,silicone wax, or combinations thereof.

Clause 9: The coating composition of any of clauses 1-8, wherein thecoating composition further comprises a dispersible acrylic resin.

Clause 10: The coating composition of clause 9, wherein the acrylicresin has an acid value of 10 to 100 mg KOH/g.

Clause 11: The coating composition of any of clauses 9-10, wherein theacrylic resin comprises greater than 50 weight % methyl (meth)acrylatebased on the total weight of the acrylic resin.

Clause 12: The coating composition of any of clauses 9-11, wherein theacrylic resin has a glass transition temperature of greater than 40° C.

Clause 13: The coating composition of any of clauses 1-12, wherein thecoating composition is a powder coating composition.

Clause 14: The coating composition of any of clauses 1-13, wherein thecoating composition further comprises a crosslinker.

Clause 15: The coating composition of any of clauses 1-13, wherein thecoating composition is completely free of a crosslinker.

Clause 16: A substrate at least partially coated with the coatingcomposition of any of clauses 1-15.

Clause 17: A method of preparing a chemical agent resistant coatingcomposition comprising mixing a fluoropolymer, a flatting agent suchthat the flatting agent comprises at least 10 weight % of thecomposition based on the total solid weight of the coating composition,and a hydrophobic additive comprising a wax, wherein when the coatingcomposition is applied to a substrate and cured as a coating, thecoating has an 85° gloss of less than 3.5, a water contact angle ofgreater than 80°, and desorbs a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate, according to testing under MTL-PRF-32348.

Clause 18: The method of clause 17, further comprising dispersing themixture in water.

Clause 19: The method of any of clauses 17-18, further comprising dryingthe mixture to form a powder coating composition.

Whereas particular embodiments of this invention have been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims.

The invention claimed is:
 1. A chemical agent resistant coatingcomposition comprising: a fluoropolymer, a flatting agent comprising atleast 10 weight % based on the total solids weight of the coatingcomposition; and a hydrophobic additive comprising a wax, wherein whenthe composition is applied to a substrate and cured as a coating, thecoating has an 85° gloss of less than 3.5, a water contact angle ofgreater than 80°, and desorbs a maximum of 180 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 40 micrograms of O-pinacolylmethylphosphonofluoridate, according to testing under MIL-PRF-32348. 2.The coating composition of claim 1, wherein the coating has a watercontact angle of greater than 100°.
 3. The coating composition of claim1, wherein the coating desorbs a maximum of 80 micrograms ofbis(2-chloroethyl) sulfide and a maximum of 35 micrograms of O-pinacolylmethylphosphonofluoridate.
 4. The coating composition of claim 1,wherein the fluoropolymer comprises polyvinylidene fluoride,chlorotrifluoroethylene copolymer, or a combination thereof.
 5. Thecoating composition of claim 1, wherein the flatting agent comprises ametal hydroxide, metal oxide, silica, a hyperbranched (meth)acrylicpolymer, a polyurea particle, a polyolefin particle, ground fiberglass,or mixtures thereof.
 6. The coating composition of claim 1, wherein thefiberglass comprises an average size dimension of 30 to 70 microns. 7.The coating composition of claim 1, wherein the wax is a fluorinatedwax.
 8. The coating composition of claim 1, wherein the wax comprisespolytetrafluoroethylene wax, polytetrafluoroethylene-modifiedpolyethylene wax, polytetrafluoroethylene-modified polypropylene wax,polyethylene wax, polypropylene wax, paraffinic wax, carnauba wax,silicone wax, or combinations thereof.
 9. The coating composition ofclaim 1, wherein the coating composition further comprises a dispersibleacrylic resin.
 10. The coating composition of claim 9, wherein theacrylic resin has an acid value of 10 to 100 mg KOH/g.
 11. The coatingcomposition of claim 9, wherein the acrylic resin comprises greater than50 weight % methyl (meth)acrylate based on the total weight of theacrylic resin.
 12. The coating composition of claim 9, wherein theacrylic resin has a glass transition temperature of greater than 40° C.13. The coating composition of claim 1, wherein the coating compositionis a powder coating composition.
 14. The coating composition of claim 1,wherein the coating composition further comprises a crosslinker.
 15. Thecoating composition of claim 1, wherein the coating composition iscompletely free of a crosslinker.
 16. A substrate at least partiallycoated with the coating composition of claim
 1. 17. A method ofpreparing a chemical agent resistant coating composition comprisingmixing a fluoropolymer, a flatting agent such that the flatting agentcomprises at least 10 weight % of the composition based on the totalsolid weight of the coating composition, and a hydrophobic additivecomprising a wax, wherein when the coating composition is applied to asubstrate and cured as a coating, the coating has an 85° gloss of lessthan 3.5, a water contact angle of greater than 800, and desorbs amaximum of 180 micrograms of bis(2-chloroethyl) sulfide and a maximum of40 micrograms of O-pinacolyl methylphosphonofluoridate, according totesting under MIL-PRF-32348.
 18. The method of claim 17, furthercomprising dispersing the mixture in water.
 19. The method of claim 17,further comprising drying the mixture to form a powder coatingcomposition.